SLVSFU7B July 2022 – April 2024 TPS929240-Q1
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
Because the TPS929240-Q1 supports PWM control for adjusting LED brightness, the voltage on OUTXn is like a pulse waveform. The output voltage and current ramp up to the target value in a certain period of time after the channel is turned on depending on the value of capacitor on the OUTXn pin. The ramping up period is proportional to the capacitance value of the capacitor. To avoid the output voltage of each OUTXn is measured in the ramping up transient period, the TPS929240-Q1 integrates a t(BLANK) timer which is programmable by a 4-bit register BLANK to setup the blanking time for all OUTXn. The device does not start the OUTXn diagnostics and ADC measurement until the t(BLANK) timer is overflow. The t(BLANK) timer is programmable from 20 μs to 4 ms as described in the Table 6-2. TI recommends to set the t(BLANK) less than the PWM dimming period which is programmable by PWMFREQ register, otherwise the OUTXn diagnostics and ADC measurement only operates properly when PWM duty cycle is set to 100%.
Blank Time | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Binary Code | 0000 | 0001 | 0010 | 0011 | 0100 | 0101 | 0110 | 0111 | 1000 | 1001 | 1010 | 1011 | 1100 | 1101 | 1110 | 1111 |
t(BLANK) (μs) | 100 | 20 | 30 | 50 | 80 | 150 | 200 | 300 | 500 | 800 | 1000 | 1200 | 1500 | 2000 | 3000 | 4000 |